australia; rainwater use in urban communities - victorian government

8/3/2019 Australia; Rainwater use in urban communities - Victorian Government

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Rainwater Use in Urban CommunitiesGuidelines for Nondrinking Applications in Multi-residential, Commercial and Community Facilities


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This document has been prepared in good faith, exercising due

care and attention. However, no representations or warranties

are expressed or implied in relation to the relevance, accuracy,

completeness or fitness for the purpose of this document, in

respect to any particular users circumstances.

Users of this document should, where necessary, seek expert

advice on managing their rainwater system.

The Department of Human Services shall not be liable to any

person or entity with respect to any liability, loss or damage

caused by or alleged to have been caused, directly or indirectly,

by this publication.

Published by the Victorian Government

Department of Human Services

Melbourne, December 2007

Also published on www.health.vic.gov.au/environment

State of Victoria

The publication is copyright. No part may be reproduced by

any process except in accordance with the provisions of the

Copyright Act 1968.

Authorised by the Victorian Government, 50 Lonsdale Street,

Melbourne


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1 Introduction 4

2 Objectiveandscope 5

3 Preventiveriskmanagement 6

4 Regulatoryframework 7

4.1 Legislation 7

4.1.1 Acts 7

4.1.2 Regulations 7

4.2 Guidance documents 7

5. Developingarainwater

managementplan 8

5.1 Organisational commitment 8

5.2 System analysis and management 8

5.2.1 System description 8

5.2.2 Hazard identification and risk assessment 8

5.2.3 Control measures 12

5.2.4 Monitoring and corrective actions 15

5.3 Putting the plan together 18

5.3.1 Roles and responsibilities 18

5.3.2 Communication 18

5.3.3 Training 19

5.3.4 Incident management 19

5.3.5 Documentation 20

5.4 Review and improvement 20

Appendices 21

Appendix1:Further information 21

Appendix2: System assessment

hazard identification and control template 22

Appendix3: Risk assessment 27

Appendix4: Chemicals of

potential concern 28

Appendix5: Incident rainwater treatment

microbial contamination 30

Contents

Rainwater Use in Urban Communities iii


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Rainwater Use in Urban Communities

Roof-collected rainwater is widely recognised as a valuable and

sustainable water resource. In many areas it can provide a

readily accessible water supply that is a low-risk alternative to

the use of reticulated drinking water.

Businesses, community groups, sporting clubs and residential

developments can supplement their water supply with rainwater

to save drinking water resources and provide increased

water security.

In urban communities rainwater can be used for a range of

purposes, including personal washing, toilet flushing, laundry

use, surface and equipment washing, topping up spas and

pools, garden irrigation, cooling and heating, and many

industrial processes.

It is not recommended that rainwater is used for drinking or

food preparation in areas where a reticulated drinking water

supply is provided, as the quality of rainwater is not as reliableas urban drinking water supplies.

Irrespective of how rainwater is used, a risk management

plan should be developed and implemented to make sure the

rainwater is safe for use.

1Introduction


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These guidelines are for people responsible for establishing and

managing rainwater schemes in urban communities. They aim

to guide the development of a risk management plan for the

provision of rainwater that is safe for use.

These guidelines apply to multi-residential (comprising two or

more households with a common rainwater collection and use

system), commercial and community sites that collect rainwater

from roofs to supplement their water supply in areas with a

reticulated drinking water supply.

Examples of sites covered by this guideline include:

shopping centres or retail businesses

commercial sites such as office blocks and

conference centres

accommodation establishments such as hotels, motels, guest

houses and camping grounds residential complexes, such as apartment blocks or clusters

of residences that have shared rainwater facilities

community facilities such as halls, sports and recreation

facilities, public amenities and community gardens

education centres such schools, higher education centres

and pre schools

industrial premises

construction and building sites

These guidelines do not apply to the use of rainwater as aprivate drinking water supply, nor do they apply to the collection

and use of stormwater (that is, urban surface run-off captured

from rain events).

2Objectiveandscope


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3Preventiveriskmanagement

Preventive risk management systems are used to assure good

water quality by focusing on the prevention of substandard

water being delivered for use. These guidelines have been

developed using the preventive risk management principles that

underpin theAustralian drinking water guidelines (2004) and the

Australian guidelines for water recycling(2006), which promotethe use of a framework that encompasses the following areas:

1.Commitmenttoresponsibleuseandmanagementof

rainwater.

This involves commitment to the development and

implementation of a risk management plan to support safe

use of rainwater (covered here in Section 5.1).

2.Systemanalysisandmanagement.

This involves understanding the entire rainwater system,

the hazards and events that can compromise rainwaterquality and the controls and monitoring necessary for risk

minimisation, thereby assuring the safe supply and use of

rainwater (covered here in Section 5.2).

3.Supportingrequirements.

These requirements include fundamental elements that

ensure the risk management system is effective, such as

employee training, and systems for documentation and

reporting (covered here in Section 5.3).

4.Review.

This includes processes to ensure that the managementsystem is operating well and areas for improvement are

identified (covered here in Section 5.4).


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The quality and acceptable uses of rainwater are not subject

to specific regulation in Victoria. Despite this, individuals

or organisations responsible for rainwater systems in urban

communities should demonstrate due diligence by ensuring

that rainwater is safe for its intended use. The quality of

rainwater and the associated management controls need to beproportional to the level of exposure to rainwater - the more

likely it is that rainwater will be ingested, the higher the water

quality and more stringent the management controls need to be.

The Department of Human Services recommends that

rainwater isnotused for drinking and food preparation

in areas where a water authority supplies reticulated

(or "mains") drinking water. This is because the quality

of rainwater is generally not as reliable as mains

supplies, which have been treated to a level to ensure

they are safe for human consumption.

The installation and use of rainwater systems in some settings

is subject to specific regulation in Victoria, as described in this

section. There are also a number of guidelines and standards

that have been developed for the use of rainwater. Contact

details for the organisations mentioned in this section are

provided in Appendix 1.

4.1Legislation

4.1.1Acts

Acts of relevance to rainwater systems include:

Health Act 1958

Building Act 1993

Planning and Environment Act 1987

Occupational Health and Safety Act 2004

Food Act 1984

The Health Act makes provision for the prevention and

abatement of conditions and activities, which are, or may be

offensive or dangerous to public health.

The regulatory requirements for on-site plumbing work in

Victoria are stated under Part 12A of the Building Act. This Act

establishes the Plumbing Industry Commissions function to

determine relevant plumbing regulations.

Some aspects of rainwater schemes may require approval

or a permit from the local council under the Planning and

Environment Act and the Building Act. Contact the local council

for further information on this.

The Occupational Health and Safety Act sets out the legal

responsibilities for employers to provide and maintain so

far as is practicable a working environment that is safe and

without risk to health. This means that the installation and use

of rainwater systems in workplaces must not place employee

health at risk.

The Food Act requires food businesses to use drinking (or

potable) water for all food preparation activities. Therefore the

use of rainwater for food preparation at these sites may not be

appropriate, unless it is treated to drinking water standards.

4.1.2Regulations

The Plumbing Regulations 1998 set the requirements andcompetencies for licensing and registering industry operatives

and specify the minimum technical standards for all on-site

plumbing work. These regulations are due for renewal in 2008.

4.2Guidancedocuments

Relevant guidelines and standards include:

Plumbing Industry Commission technical information on the

plumbing of rainwater systems.

The Rainwater tank design and installation handbook

HB 230-2006 published by the Australian Rainwater Industry

Development Group, which can be purchased at

www.arid.asn.au or through Standards Australia.

Australian Standards and Australian Technical Specifications,

including (but not limited to):

-AS/NZS 3500 National plumbing and drainage code

-ATS 5200 Technical specification for plumbing and drainage

products

-AS/NZS 2179 Specifications for rainwater goods, accessories

and fasteners

-AS 1273 Unplasticized PVC (UPVC) downpipe and fittingsfor rainwater

-AS/NZS 4130 Polyethylene (PE) pipes for pressure applications

-AS/NZS 4766 Polyethylene storage tanks for water and

chemicals

4Regulatoryframework


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5.Developingarainwatermanagementplan

Rainwater that is clear, has little taste or smell, is free from

suspended material, and comes from a well-maintained roof

catchment system, is likely to be suitable for most uses.

However, it is important to realise that this is not a guarantee of

safety as contamination is not always visible.

Rainwater systems should be designed, installed and

maintained in a manner that protects rainwater from

contamination. A rainwater management plan that is

underpinned by preventive risk management principles is

the most effective way of achieving this.

The complexity of the management plan should be proportional

to the potential level of risk: schemes where there is a higher

risk of ingesting rainwater (such as those involving personal

washing) will generally require a more detailed assessment and

more stringent controls than schemes where there is a low risk

of ingestion (such as those involving garden watering). Refer toTable 1 for more detail on the likely risk of ingestion with

various uses.

This section discusses the components of an effective

management plan.

5.1Organisationalcommitment

It is essential that the management of the organisation that

owns or maintains the roof catchment and the rainwater

scheme is committed to the development and implementation

of the rainwater management plan. Management should have

a clear understanding of the principles of preventive risk

management and ensure that adequate funding is allocated to

the development of the plan, and ongoing maintenance of the

scheme. Additional responsibilities are discussed in

Section 5.3.

5.2Systemanalysisandmanagement

A systematic assessment to identify hazards to water quality

and appropriate controls for these will underpin the rainwater

management plan. Where possible, specific controls for the

management of potential health risks associated with rainwateruse are provided in this section. However, not all rainwater

systems are identical and so a one size fits all approach to

risk management is not appropriate. Therefore, identification

of site-specific risks and measures to control these will be

required for each scheme. A template for undertaking a system

assessment for the risk management plan (which includes some

generic hazards and management controls) is provided

in Appendix 2.

This section discusses the important elements of the system

assessment in more detail.

5.2.1Systemdescription

An essential prerequisite for hazard identification and risk

assessment is to detail each component of the rainwater

system. This system description provides the basis for hazard

identification, risk assessment and control.

The rainwater system is defined as everything from the

collection or catchment of rainwater through to the end-user or

receiving environment.

This system description should cover:

The roof catchment and storage, including roof, guttering,down pipes and rainwater storage tanks.

The supply system (distribution and plumbing) including the

pipe specifications and plumbing installation controls.

Treatment processes, such as filtration or disinfection units (if

applicable)

Intended uses of the rainwater.

A flow chart can help to schematically illustrate the system.

5.2.2Hazardidentificationandriskassessment

Hazards and hazardous events should be identified for eachcomponent of the rainwater system identified in the

system description.


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Hazardversusrisk

Hazards and hazardous events that are considered relevant to most

rainwater systems are included in the template in Appendix 2.

Any additional hazards and hazardous events that are considered to be

of significant risk should be identified on a case-by-case basis. Further

guidance on assessing the risk of a hazardous event can be foundin Appendix 3.

The terms hazard and risk are often confused or used

interchangeably. In this context:

A hazard is a biological, chemical, physical or radiological

agent that has the potential to cause harm.

A hazardousevent is an incident or situation that can

lead to the presence of a hazard (what can happen,

and how).

Arisk is the likelihood of identified hazards causing harm

in exposed populations in a specified timeframe, including

the severity of the consequences.

The distinction between hazard and risk is important to

ensure that management controls are proportional to the

risk posed by the hazard (stringent management controls

should not be directed at hazardous events that have a low

likelihood of occurring with low severity).

Key hazards in rainwater include microorganisms and

chemicals that pose a risk to human health if ingested.

Some examples of hazardouseventsthat can lead to an

actual risk include:

Microbial contamination of rainwater due to birds or other

animals on roof catchment.

Contamination of rainwater with chemicals as a result of

leaching from roof and plumbing materials, or atmospheric

deposition.


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Microbialhazardsandhazardousevents

While the quality of rainwater collected from rooftops is

generally good, it may contain a range of disease-causing

(pathogenic) microorganisms including bacteria and parasites.

These may arise from the faeces of birds, reptiles, amphibians

and mammals that have access to the roof or tank, or be

free-living environmental organisms.

Animal faeces can carry pathogenic bacteria including

Campylobacterand Salmonella species and parasites such as

Cryptosporidium and Giardia that are infectious to humans.

These microorganisms have been associated with disease

outbreaks from rainwater tanks and are considered the most

significant risk to human health.

Consideration also needs to be given to the potential for some

microorganisms to grow within rainwater tanks, or in pools of

stagnant water within the rainwater system. While most humanpathogens are unlikely, or unable, to grow in rainwater tanks,

there are some bacterial pathogens, such as Legionella and

Pseudomonas, that can grow in water under the right conditions.

This growth is generally dependant on the availability of

nutrients and the water temperature.

Algae and cyanobacteria (also called blue-green algae) may also

grow in rainwater tanks if they allow sufficient light in and the

rainwater contains sufficient nutrients. Many algae species can

affect the taste, appearance and odour of the water, and some

species of blue-green algae can produce toxins that may cause

skin irritation and illness.

It is possible that rainwater from poorly maintained systems

may contain nutrients and as a result could support microbial

growth, particularly during long periods of warm weather when

tank water temperatures increase.

Mosquitoes

In addition to direct health risks associated with the ingestion

of rainwater, rainwater tanks may pose indirect health risks by

providing breeding sites for mosquitoes, which can

transmit disease.

Although rainwater tanks have not been associated with

outbreaks of mosquito-borne disease in Victorian urban areas to

date, increasing numbers of rainwater tanks in urban areas may

provide additional breeding sites for mosquitoes and increase

the likelihood of disease transmission.

10 Rainwater Use in Urban Communities


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Chemicalhazardsandhazardousevents

Chemical hazards may contaminate rainwater via the following:

Dust, atmospheric deposits, and leaf litter on roof surfaces.

Leaching from roofing, guttering and plumbing materials, or

materials used to manufacture the storage tank.

Discharges from roof-mounted appliances (such as air

conditioners, hot water services and flues).

Air pollutants from industrial or domestic discharges, motor

vehicle exhaust fumes, and horticultural chemicals used

at farms or in home gardens. In rural areas, the amount

of air pollution from industry and traffic will be reduced

compared to urban areas. However, there may be greater

risk of contamination from agricultural chemicals including

pesticides and fertilisers.

The risk of chemical contaminants in rainwater causing harm,when the rainwater is used for purposes other than drinking,

is likely to be low in most circumstances. Basic controls will

further reduce these risks.

However, an individual assessment of chemical risks is

recommended for all schemes where rainwater is used for

purposes with a moderate risk of ingestion (refer to Table 1).

A general suite of chemicals of potential concern is provided

in Appendix 4 (Table A4.1), and a local assessment should be

undertaken to identify any additional chemicals of potential

concern (for example from industrial emissions in the vicinity of the

scheme). For chemicals of potential concern, sampling shouldbe undertaken to establish baseline rainwater concentrations.

To determine whether concentrations of chemical contaminants

are of concern, theAustralian drinking water guidelines (2004),

available from the National Health and Medical Research

Council, can be referred to as a starting point. These guidelines

would be considered conservative for schemes where rainwater

was not being used for drinking. Therefore, if the concentration

of a chemical contaminant exceeded the guidelines it would not

necessarily be cause for concern, but rather, would warrant a

more detailed risk assessment.

Certain characteristics of rainwater may also cause aesthetic

or other physiochemical issues, such as staining of laundry or

corrosion of plumbing fittings. A general suite of parameters,

along with suggested guideline values, is provided in Appendix 4

(Table A4.2).

The risk from asbestos is one that is commonly raised in

relation to rainwater systems. Asbestos is no longer used

in new houses, but may be present in some older roofs.

Asbestos fibres are dangerous to health when inhaled in

sufficient quantities, but are not believed to pose a risk viarainwater harvesting systems. Where possible, asbestos

roofing should be left undisturbed, as fibres can be released

into the air by actions such as cutting, grinding or drilling.

High-pressure roof cleaning methods should also be

avoided. Where the roof catchment area has deteriorated

badly, it should be replaced with asbestos-free substitutes.

Rainwater Use in Urban Communities 11


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5.2.3Controlmeasures

Control measures should be identified for all significant risks.

Identification of control measures requires consideration of the

multiple barrier approach. The strength of this approach is that

if one control measure (or barrier) fails, the remaining control

measures will minimise the likelihood of contaminants passing

through the entire system and being present in sufficient

amounts to cause harm to rainwater users.

Control measures for rainwater systems would typically include:

Roof catchment protection and maintenance.

Correct material selection and installation of the rainwater

storage, distribution and plumbing.

Treatment, such as filtration and disinfection, where

deemed necessary.

Regular inspection and maintenance of the supply system(pipes, tanks, pumps and other elements).

Control measures that are generic to most rainwater systems

are discussed in this document, and summarised in the

template in Appendix 2. However, the individual system

assessment may identify that additional control measures

are required.

Roofcatchmentprotectionandmaintenance

Using correctly designed and maintained roof catchments is

a key step to protecting rainwater from contamination. For all

systems, the following should be implemented:

Overhanging vegetation should be cut back.

Gutter shielding devices (gutter guard) should be installed

where roof catchments are adjacent to trees and vegetation,

to reduce the amount of debris entering gutters and

storage tanks.

Gutters should have sufficient and continuous fall to

downpipes to prevent pooling of water, which could

accumulate debris, lead to algal growth and possibly provide

a site for mosquito breeding. A fall of 1:500, or 1:200 for box

gutters and internal guttering, should be sufficient (consistentwith AS/NZS 3500 National drainage and plumbing code).

Overflows and bleed-off pipes from roof-mounted appliances,

such as cooling systems and hot water services should not

discharge onto the rainwater catchment.

Chemicals used for any roof cleaning should be carefully

selected to ensure they do not pose a risk to human health or

the environment.

Sections of roof affected by emissions from any industrial

processes within the building should be excluded from the

rainwater catchment.

The following measures are generally considered good practice,

but are most important where rainwater is used for purposes

with a moderate risk of ingestion, or where rainwater is used to

water vegetables for human consumption:

First flush diverters or by-pass devices should be installed to

reduce the entry of contaminants, which build up on roofs

and in gutters during dry spells, to the storage tank.

Flues from slow combustion heaters should be installed in

accordance with the relevant Australian Standards.

Lead flashing should be removed.

Rainwater should not be harvested from roofs coated in

bitumen products or lead-based paints, or roofs affected by

emissions from industrial processes within the building.

Exposed preserved or treated timber should be sealed, or the

section of roof containing the timber should not be used for

collection of rainwater.

Roof access should be restricted to maintenance

activities only.

Structures that provide a perching place for birds should beremoved or modified.


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Rainwaterstorage

Rainwater tanks are available in a range of materials including

galvanised steel, fibreglass, polyethylene, concrete and a

number of proprietary products. All can be suitable, providing

the materials used will not contaminate the rainwater, and they

comply with the relevant Australian Standards.

Tanks should be assembled and installed in accordance with

the manufacturers requirements and be structurally sound.

Tanks should also be installed in accordance with any local

council requirements (contact the relevant local council for

further information).

In-ground tanks need to be properly sealed and access points

need to be protected against surface run-off, groundwater and

soils. Tanks should not be buried in contaminated ground, near

underground chemical or petroleum storage tanks, or near

septic tanks.

Tanks should have impervious covers and all access points,

except for the inlet and overflow, should be provided with close-

fitting lids which should be kept shut unless in use. The inlet to

the tank should incorporate a screen to prevent material being

washed into the tank, and a mesh covering to prevent access of

mosquitoes and other insects. Overflows should also be covered

with insect-proof mesh.

Tanks should be lightproof to minimise algal growth.

All products and materials used for connections to and from the

rainwater tank should comply with current Australian Standardsand plumbing regulations. Wherever possible, all sections of inlet

pipes should be directed down and rainwater should flow into the

top of the tank. The inclusion of rising sections of pipework or

charged downpipes should be avoided, where possible, as they

provide potential traps for sediments and stagnant water.

Run-off that is not collected in the tank and tank overflows must

be diverted into the stormwater drain. It must not be allowed

to pool or to cause a nuisance to neighbouring properties or

to areas of public access. The overflow should be designed to

prevent stormwater from flowing back into the tank.

Rainwaterdistributionandplumbing

A licensed plumber should install the rainwater distribution

system in accordance with AS/NZS 3500 National drainage and

plumbing code, and any relevant Plumbing Industry Commission

guidance (contact details in Appendix 1).

To prevent cross connections between the rainwater and

mains water supplies, rainwater distribution pipes should be

clearly labelled, with RAINWATER in a contrasting colour,

in accordance with AS/NZS 3500 National drainage and

plumbing code. In addition, as-built drawings of the distribution

system should be available and protocols developed to ensure

modifications and maintenance on the distribution system do

not result in a cross connection.

Rainwater systems in urban areas will often have a mains water

supply incorporated to provide the system with water in periods

of no rainfall. This is particularly important where rainwater isused to supply essential services such as toilets. Water retailers

do not usually allow the direct connection of the reticulated

drinking water supply to rainwater systems, and require the use

of backflow prevention devices to prevent the risk of rainwater

siphoning back into and contaminating the drinking water

supply. Information on this should be sought from the local

water retailer or the Plumbing Industry Commission. Backflow

prevention devices must comply with Australian Standards.


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Rainwatertreatment

As rainwater collected from well-maintained rooftops is

generally of a quality that is safe for many uses, the need for

treatment is unlikely. However, in some circumstances there

may be a need to treat rainwater.

It is recommended that rainwater systems that serve multi-

residential, commercial and community sites incorporate

treatment to remove microbial hazards when rainwater uses

have a moderate risk of ingestion (for example bathing,

showering and hand basins). This is particularly important when

elderly, very young or people with suppressed immune systems

are likely to be using rainwater.

There is a moderate risk of ingesting rainwater when it is used

in swimming pools and spas. Most swimming pools and spas

incorporate some form of treatment (for example chlorination),

which should effectively manage potential health risks inrainwater in most scenarios. Therefore specific rainwater

treatment is unlikely to be required for these.

Treatment options for rainwater systems most commonly

include:

Filtration; and/or

Disinfection (usually chlorine disinfection or ultraviolet light

(UV) disinfection).The type and level of treatment required depends on the

hazards that require control. In most cases, treatment by

disinfection should be sufficient if the contaminants of concern

are microbial, and the rainwater has little suspended material

and is of low turbidity (indicatively


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End-usecontrols

Rainwater users should be aware of the appropriate uses of

rainwater. Communication tools should be developed that are

appropriate for the particular scheme in communicating key

messages about the rainwater system and its intended and

unintended uses (refer to Section 5.3).

External taps supplying rainwater should be identified with

a safety sign labelled RAINWATER. It is recommended that

signs comply with AS1319 Safety signs for the occupational

environment, with black writing on a yellow background. Where

sensitive groups are involved, who may not obey signage (for

example childcare centres), additional controls should be

considered such as using taps with removable handles or

locating taps 1.5 metres or more above the ground.

Internal rainwater outlets should be identified, for example via

a RAINWATER label on tap buttons.

5.2.4Monitoringandcorrectiveactions

Monitoring the rainwater system is an essential part of the

overall multiple barrier approach. The results of monitoring

show whether the risk control measures are working properly.

Corrective actions are required when monitoring indicates that

a control measure or barrier has not been operating effectively.

Whether the water is treated or not, a full rainwater system

inspection should be undertaken at least quarterly. Things to

look for include:

Checking the roof and gutters to ensure they are in good

condition, clean, that any appliances are not discharging

contaminants onto the roof catchment, and that barriers

such as leaf guards and first flush diverters are clear and

working properly.

Checking rainwater storage tanks to ensure they are in good

structural condition, there is no evidence of contaminating

matter leaching into tanks, any protective mesh is intact, and

that there are no signs of contaminating matter (including

dead animals) or build up of sediment in tanks.

Checking for cross connections by turning off the mains

water supply at the water meter and checking drinking water

taps if water continues to flow through drinking water taps

when the mains water is switched off then a cross connection

has occurred. Note that this is only necessary when pipes

carrying rainwater are in close proximity to those carrying

drinking water, for example when rainwater is used indoorsfor toilet flushing, laundry or personal washing.

Maintaining any pumps and plumbing.

Checking and maintaining any backflow prevention devices,

in accordance with Australian Standards.

Checking any signage is in place and in good condition.

Periodically monitoring for chemicals of concern, if applicable.

Other monitoring requirements should be identified during the

hazard identification and risk assessment process. For example,

if the risk of chemical contamination causing harm to rainwater

users is deemed to be a significant risk, then the chemical

quality of the rainwater should be tested.


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Monitoringtreatmentprocesses

Regular checking and maintenance of water treatment systems

is important to ensure that the water supply continues to be

safe. The following monitoring is recommended, at a minimum,

for treatment processes:

Filtration

All monitoring, maintenance and corrective actions for

filtrations systems should be undertaken in accordance with

the manufacturers advice.

Water quality should be regularly checked after filtration.

If the flow decreases or the water becomes turbid (dirty or

cloudy) the filter needs to be checked and may need servicing.

Chlorination disinfection systems

Chlorine injection units should be checked to ensure they are

fully operational and have an adequate supply of chlorine atleast weekly.

Where chlorine is used, it is desirable to have a free chlorine

residual of at least 0.5 mg/L after 30 minutes. This should be

checked weekly, using a suitable chlorine test kit (available

from swimming pool equipment suppliers).

If the chlorine residual is found to be too low, then

modifications to the dosing system should be made as soon

as possible.

UV disinfection systems

The effectiveness of a UV disinfection system depends onthe water quality, flow rate and hydraulics, intensity of UV

radiation, amount of time the microorganisms are exposed to

the radiation, and the reactor type and configuration.

A monitoring, cleaning and maintenance schedule for UV

disinfection systems needs to be established based on the

advice of the manufacturer and a water treatment specialist

for the system to remain effective.

All disinfected systems

If the treatment processes used have been designed for

the removal of microorganisms, then rainwater should be

periodically tested for the organism Escherichia coli. The

presence of E. coliindicates that people using rainwater

could be exposed to disease-causing microorganisms.

Samples should be taken from the tank outlet or from taps

within the distribution system. E. colishould not be detected

in 100mL. If detected, corrective actions should be taken

as soon as possible (for example through batch dosing the

storage with chlorine (refer to Appendix 5) and resampling).

It is recommended that this testing is undertaken at

least quarterly.

To ensure the highest level of accuracy, water samples

should be tested at a laboratory that is certified as having

appropriate quality assurance programs for the analysisrequired, for example National Association of Testing

Authorities (NATA) accredited - refer to Appendix 1 for

contact details.


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Table1:Treatmentandmonitoringrecommendationsforrainwaterinurbancommunities

Use

Risk of

ingestion Treatment

Recommended minimum monitoring

System

inspection

Treatment

process E. coli Chemicals

Personal washing

(showers, baths and hand basins)

Moderate Recommended Quarterly Consult

manufacturer or

water treatment

specialist.

Quarterly1 Every 3 years2

Swimming pool/spa Moderate See note 3 Quarterly N/A N/A4 Every 3 years2

Laundry (trough and washing

machine)

Toilet flushing

Garden watering and general

outdoor use5

Fire protection systemsOpen industrial systems

Low Unlikely to be

necessary6

(Unless hazard

identification and

risk assessment

indicates that

significantrisks require

management)

Quarterly N/A N/A4 N/A7

Garden watering (subsurface

or drip irrigation)

Heating and cooling systems

(including cooling towers8)

Closed industrial systems

Extremely

low

Unnecessary6 Quarterly N/A N/A4 N/A7

Notes:

1. It may be appropriate to increase the frequency of E. colimonitoring if rainwater is used for susceptible groups, such as elderly, immune-suppressed or

very young.

2. More frequent monitoring of chemicals may be appropriate if the initial sampling and risk assessment indicates that chemical concentrations are close to

levels of health concern, or if treatment processes are being used to remove chemicals of health concern.

3. Swimming pool and spa water treatment processes, such as chlorination, should meet treatment needs in most cases (unless chemicals are assessed as

being of concern see Appendix 4). Public pool operators should refer to the Pool operators handbook, available from the DHS website, for

further information.

4. E. colimonitoring is usually unnecessary if rainwater is untreated. However, if treatment such as disinfection is used then E. colimonitoring may be an

appropriate indicator of treatment effectiveness.

5. Garden watering includes vegetable gardens. General outdoor use includes car washing, dust suppression, construction, wash down, and filling water

features and ponds.

6. Treatment is generally considered unnecessary from a human health risk perspective. In some circumstances it may be necessary to treat rainwater to

remove chemical contaminants that may damage appliances or industrial systems.

7. Monitoring may be appropriate for chemicals of aesthetic or physiochemical concern (refer to Appendix 4).

8. Under the Building Act 1993 a specific risk management plan is required to control the risk of Legionnaires disease from cooling tower systems. Contact

the Department of Human Services for further information refer to Appendix 1 for contact details.


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5.3Puttingtheplantogether

The outcomes of the system assessment need to be

documented in the risk management plan, along with the

elements that support the effectiveness of the plan:

Roles and responsibilities

Communication

Training

Incident management

These areas are discussed in further detail in this section.

5.3.1Rolesandresponsibilities

Schememanager

The scheme manager is the person or organisation responsible

for overseeing the installation and operation of the rainwatersystem. A scheme manager could include a property owner,

body corporate, property manager, business owner,

sporting club, etc.

The scheme manager should demonstrate due diligence and

ensure that the legal risks associated with the use of rainwater

are appropriately addressed. To fulfil this responsibility scheme

managers should ensure that their rainwater system is managed

in accordance with these guidelines, including the development,

implementation and review of the rainwater management plan,

and ensuring communication and training needs are

adequately met.

The scheme manager should be familiar with any legislation,

Australian Standards and guidelines relevant to the use of

rainwater.

In many cases the scheme manager will be the same entity as the

scheme operator.

Schemeoperator

The scheme operator is the person or organisation responsible

for operating and maintaining the rainwater system. These

responsibilities include monitoring activities and corrective

actions the specifics of which need to be clearly documented

in the risk management plan.

In some cases, a number of individuals or organisations may

have operation and maintenance responsibilities. If this is the

case then this should be clearly documented.

5.3.2Communication

A communication program is an important component of

a rainwater scheme, and should be documented in the risk

management plan. Key messages to be communicated to users

of the system should address:

Appropriate uses of rainwater.

Inappropriate or potentially unsafe uses of rainwater.

How to identify rainwater pipes and outlets.

Where to get further information and advice.

How to report rainwater supply or quality issues.

For residential developments, it is recommended that residents

are provided with communication material when the scheme

is established, and on change of ownership or tenancy. Yearly

reminders of the key messages should be provided to

each household.

For other facilities, written communication packages may

not always be appropriate. In these cases the best tools to

communicate the key messages about the rainwater systems

should be identified and documented in the rainwater plan.

These tools may include, but are certainly not limited to, site

induction programs, school education programs, and

additional signage.


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5.3.3Training

The scheme operators should be knowledgeable and

adequately trained in the operation of and the risks associated

with the use of the rainwater system. Specifically, they should

be familiar with the system assessment and riskmanagement plan.

Where a rainwater system is used within a workplace or

commercial environment, employee training may be required

that covers (depending on the role of the employee):

The principles of risk management.

Knowledge and awareness of the rainwater management

plan, including roles and responsibilities of

individuals and agencies, both internal and external.

The rainwater system, including its operation and the control

measures that are in place to protect human health (forexample system maintenance, monitoring, testing

and sampling).

Training can take place in a number of forms. It may include

formal induction and training sessions with manuals, or the

use of newsletters, briefings and meetings. Regardless of

which method is used, employees should be encouraged to

communicate and think critically about the aspects of their

work that relate to, or may affect, the rainwater system and use

of rainwater.

All training activities should be documented in the rainwatermanagement plan.

5.3.4Incidentmanagement

The risk management plan should include the development of

responses to incidents that may affect on the supply or quality

of rainwater.

Incidents can be identified using the system assessment, andmay include:

Contamination of water with pathogens as a result of animal

faeces or dead animals in the roof catchment or storage

tank (note that a protocol for emergency disinfection of the

rainwater storage is provided in Appendix 5).

Blue-green algae bloom in the storage tank.

Incidents that increase the risk of potentially harmful

contaminants (e.g. treatment failure, incorrect dosing

of chemicals).

Damage to the rainwater system (roof catchment, storageor distribution) as a result of storms, floods or a natural or

human-made disaster.

Chemical contamination of the roof catchment, for example

through aerial spraying with pesticides.

Sabotage or vandalism.

Where it is determined that an incident has a reasonable

likelihood of occurring, response protocols should be developed

to ensure human health and safety risks are managed

efficiently and effectively.

Key areas to be addressed in any incident or emergency

response protocol include:

Response actions.

Responsibilities of individuals and agencies, both internal

and external.

Communicating risks to customers and staff.

Plans for alternative water supplies.

Increasing water quality monitoring and health surveillance.

It is important that employees are trained in incident and

emergency response to ensure that they can manage potential

incidents and emergencies effectively.


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5.3.5Documentation

Records of all rainwater system management and monitoring

activities should be kept, including:

System inspection results.

Equipment checks and maintenance, including any filterchange or refurbishment.

Treatment monitoring results.

Rainwater quality monitoring results.

Any adverse events, such as broken pipe work, dead animals

in the water source, cross connections and repairs to

the system.

Corrective actions taken to fix faults or prevent contamination.

Documentation requirements, the location of records, and the

individuals responsible for keeping and maintaining recordsshould be identified in the risk management plan.

5.4Reviewandimprovement

The rainwater management plan should be reviewed and where

necessary, updated to ensure that it remains effective.

The review should aim to:

Address emerging problems and trends identified throughmonitoring activities, incidents and emergencies

Identify priorities for improving the rainwater system

Assess overall performance against guidelines and

regulatory requirements

Reviews should be conducted annually.


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Appendix1:Furtherinformation

DepartmentofHumanServices

The Department of Human Services is responsible for providing

guidance for alternative water supplies to ensure that they are

protective of public health.

Phone 1300 761 874

www.health.vic.gov.au/environment

PlumbingIndustryCommission

The Plumbing Industry Commission (PIC) plays an active role in

the development and enforcement of standards and regulatory

requirements for all on-site regulated plumbing work. The PIC

monitor plumbing works and take corrective action if required.

Phone 1800 015 129

www.pic.vic.gov.au

WorkSafeVictoria

The Victorian WorkCover Authority (VWA) is the manager of

Victoria's workplace safety system. It is the responsibility of

the organisation to help avoid workplace injuries occurring and

enforce Victoria's occupational health and safety laws.

Phone 1800 136 089

www.worksafe.vic.gov.au

LocalGovernment

Local councils are responsible for local enforcement of the Food

Act1984 (which requires that potable water is used for food

preparation activities at food businesses), and provide permits

and approvals under the Planning and Environment Act 1987and

Building Act 1993, which may apply to some rainwater schemes.

StandardsAustralia

Standards Australia has developed and published a number of

standards relevant to the installation of rainwater systems.

www.standards.com.au

AustralianRainwaterIndustryDevelopment

Group

The Australian Rainwater Industry Development Group provide

technical information on the design of rainwater harvesting

and use systems. Their National Rainwater Tank Design andInstallation Handbook can be purchased through their website,

or from Standards Australia.

www.arid.asn.au

NationalAssociationofTestingAuthorities

NATA provide accreditation for laboratories and similar testing

facilities.

Phone (03) 9329 1633

www.nata.asn.au


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Hazard Hazardous event Typical control measures Monitoring Corrective actions

Roof catchment and storage

Microbial

Faecal contamination

from birds and animals

Bird perching and animal

access to roof

Prune overhanging tree

branches

Check tree growth during

system inspection

Prune branches

Remove or modify

structures that encourage

bird perching (this is

particularly important for

schemes with moderate

risk of ingestion)

Check during system

inspection

Repair or modify, as

required

Bird and animal faeces on roof Treatment, where

appropriate (refer to

table 1)

As per manufacturers

advice

For additional monitoring,

refer to table 1


advice

Animal access to tank Protect or screen all

inlets, overflows and other

openings to tank

Check access covers,

inlets, overflows and

openings during system

inspection

Repair gaps and secure

access cover

Maintain integrity of tank

roof and body

Check structural integrity

of tank during system

inspection

Repair, as required

Microbial


from humans (above-

ground tanks)

Human access to tank Prevent access

Ensure tank is roofed

and access hatches are

secured

Check access covers

during system inspection

Secure access covers

Microbial


from humans and

animals (below-groundtanks)

Contamination of rainwater

from surface water, leaking

sewerage pipes or septic tanks

Use above-ground tanks,

or protect tank from

overground flows and

ensure tank walls are intact

Check structural integrity


Check surface water does

not enter tank during stormevents

Repair or line inside of

tank. Improve barrier to

surface water flow

Appendix2:Systemassessmenthazardidentificationand

controltemplate


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Microbial

Growth in tank or

rainwater system

Growth of microorganisms in

rainwater storage tank

Keep roof catchment and

gutters clean

Install a first flush diverter to

minimise entry of nutrients

and sediments to tank (this

is particularly important for


risk of ingestion)

Use gutter guard and tank

inlet screening to minimise

entry of leaves and debris

Inspect roof, gutters and

screens at tank openings


Clean gutters

Repair or replace any

damaged screens

Growth of microorganisms in

rainwater system

Design system to prevent

pooling and stagnation

of water

Inspect gutters during

system inspection, and

periodically after rainfall

Clean gutters or make

changes to ensure they

drain quickly between rain

events

Growth of algae in rainwater

storage tank

Ensure tank is light-proof Check integrity of roof

Inspect water for presence

of visible algal growth

Repair roof

Confirm algal species and

risk to health; treat water to

remove algae if appropriate

Microbial

Other

Other source of microbial

contamination, identified on a

case-by-case basis

As appropriate As appropriate As appropriate

Mosquitoes Access to stored water Protect all tank inlets with

insect-proof mesh

Check access covers,

inlets, overflows and

openings during system

inspection

Inspect water for presence

of larvae

Repair mesh to prevent

access and if larvae are

present, to prevent escape

of mosquitoes

Add small amount of

medicinal liquid paraffinto the tank if larvae

are persistent (approx

2 tablespoons for a 10

kilolitre tank)

Access to pooled water Design system so that

potential for pooling of

water (for example in

gutters) is minimised

Keep gutters clear of debris

Inspect gutters during

system inspection, and

periodically after rainfall

Clean gutters or make

changes to ensure they

drain quickly between rain

events


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Chemical

Roof catchment

contamination

Accumulated sediments on

roof catchments

Keep roof catchment and

gutters clean and install

a first flush diverter to

minimise entry of nutrients

and sediments to tank (thisis particularly important for


risk of ingestion)

Use gutter guard or tank

inlet screening to minimise

entry of leaves

Check first flush diverter

operation during system

inspection

Inspect roof and gutters


Inspect tank sediment

levels every 2-3 years

Maintain first flush diverter

Clean gutters

Clean tank, if required

Contamination with smoke and

emissions from flues

For wood heaters, use

fuel that is not painted or

treated with preservatives,

and ensure flues are

installed according to the

appropriate AustralianStandards (this is



risk of ingestion)

For other flues, exclude

affected sections of roof

from rainwater catchment

Check choice of fuel

Check flue installation

Inspect roof before

installing tank

Discard inappropriate fuel

Address as appropriate

Overflow and discharges from

roof-mounted appliances onto

catchment

Eliminate, or exclude

affected sections of roof

from catchment

Inspect roof before

installing tank

Check during system

inspection

Make alterations,

as appropriate


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Chemical

Contamination from

roof and system

materials

Chemical leaching from roof or

system materials

Remove lead flashing

and seal any exposed

preserved/treated

timber, or exclude

affected sections of rooffrom catchment (this is



risk of ingestion)

Inspect roof before

installing tank

Remove, cover or seal,

as appropriate

Dont collect water from

roofs coated or painted

with materials that

may leach hazardous

substances (e.g. lead-

based paints or tar-based

materials)

Inspect roof before

installing tank

Remove, cover or seal,

as appropriate

Use tanks and system

components that comply

with the relevant Australian

Standards

Check suitability of

components with supplier

or retailer

Remove or replace product

Chemical

Other

Other source of chemical

contamination, for example

from atmospheric pollution

(identified on a case-by-case

basis)

As appropriate As appropriate As appropriate


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Distribution and plumbing

Microbial and chemical Cross connections between

rainwater and other water

supplies

Ensure distribution

system complies with PIC

guidance and relevant

Australian Standards

Inspect system after

installation to ensure

compliance

Inspect after modifications

or maintenance to system

to ensure compliance

Rectify non-compliant

distribution or plumbing

work

Chemical Chemical leaching from

system materials

Treatment (where applicable)

Microbial and chemical Treatment process failure Monitoring and

maintenance as per

manufacturer or water

treatment specialist advice


advice


advice

End use

Microbial and chemical Unintended use of rainwater

(e.g. drinking) causing illness

Make residents and

rainwater users aware of

appropriate uses throughcommunication tools

Ensure communication

tools or packages are

available to rainwaterusers, and updated when

necessary

Address as appropriate

Provide signage, where

appropriate

Inspect signage presence

and condition during

system inspection

Repair or replace signage

Ensure distribution and

plumbing system complies

with PIC guidance and

relevant Australian

Standards

Inspect system after

installation to ensure

compliance

Inspect after modifications

or maintenance to system

to ensure compliance

Rectify non-compliant

distribution or plumbing

work

Inspect distribution system

for cross connections

to drinking water supply

or connections to

inappropriate uses

Rectify any inappropriate

connections

Ensure backflow prevention

protects drinking water

supply at any drinking

water back-up to rainwater

system and complies with


Inspect backflow

prevention system, as per

manufacturers advice and


Repair or replace as

appropriate



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The level of risk associated with hazards or hazardous events can be estimated using this approach, adapted from theAustralian

drinking water guidelines 2004.

For each hazard or hazardous event, estimate the likelihood of occurrence (Table A3.1) and severity of occurrence (Table A3.2).

The level risk can then be identified using Table A3.3.

As a guide, it is suggested that moderate, high and very high risks are considered significant, and therefore control measuresshould be applied.

TableA3.1Qualitativemeasuresoflikelihood

Level Descriptor Example description

A Almost certain Is expected to occur in most

circumstances

B Likely Will probably occur in most

circumstances

C Possible Might occur or should occur at some

time

D Unlikely Could occur at some time

E Rare May occur only in exceptional

circumstances

TableA3.3Qualitativeriskanalysismatrix:levelofrisk

Likelihood Consequence

1 Insignificant 2 Minor 3 Moderate Major Catastrophic

A (Almost certain) Moderate High Very high Very high Very high

B (Likely) Moderate High High Very high Very high

C (Possible) Low Moderate High Very high Very high

D (Unlikely) Low Low Moderate High Very high

E (Rare) Low Low Moderate High High

Appendix3:Riskassessment

TableA3.2Qualitativemeasuresofconsequenceorimpact*

Level Descriptor Example description

1 Insignificant Insignificant impact.

2 Minor Minor impact for some rainwater

users.

3 Moderate Minor impact for all rainwater users.

4 Major Major impact for some rainwater

users.

5 Catastrophic Major impact for all rainwater users.

* An impact may include illness, complaint or interrupted supply


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Healthparameters

A general suite of chemicals of potential health concern is

provided in Table A4.1. This table can be used as a starting

point for assessing the potential risks associated with schemes

where rainwater is used for purposes with a moderate risk ofingestion (such as personal washing and swimming).

For each chemical the Australian drinking water guideline is

provided. For schemes where rainwater is not used for drinking

it is important to note that exceeding the Australian drinking

water guideline is not necessarily cause for alarm, but rather,

should warrant a more detailed risk assessment.

This is not an exhaustive list of chemicals, and a local

assessment should also be undertaken to identify any

additional chemicals of potential concern, for example from

industrial emissions or known chemicals (such as pesticide

or fertiliser) used in the vicinity of the scheme. The list may also

be reduced, if a local assessment concludes that contamination

with a particular chemical is unlikely. The local office of the

Environment Protection Authority could be contacted for further

information on local industrial emissions and the Department

of Primary Industries for information on mining or quarrying in

your area.

Monitoring should be undertaken every 3 years, to ensure the

concentration of chemicals of potential concern remain at

safe levels

TableA4.1:Chemicalsofpotentialhealthconcern

Chemical

Australian

drinking water

guideline (mg/L)

ArsenicArsenic is found in soil and rocks. It can be

released from mining activities, and by the

burning of fossil fuels and waste incineration.

It is also used in some industrial processes.

0.007

Cadmium

Cadmium may enter water supplies from

impurities in the zinc of galvanized metal, from

solders, and from some fertilisers.

0.002

Chromium

Chromium may be present in rocks and

soils. It is also used in a number of industrial

processes. The hexavalent form (Cr(VI))is considered harmful to humans. If total

chromium exceeds 0.05mg/L, then a separate

analysis for hexavalent chromium should

be undertaken.

0.05

Copper

Copper is found in many rocks and soils. It is

also frequently used in plumbing and some

industrial processes. It should be noted that

2mg/L is a health-based guideline, however,

concentrations above 1 mg/L may cause blue

or green stains on sanitary ware.

2

LeadLead may enter the water supply from

natural sources or from plumbing or roofing

components that contain lead. It can also be

present in some industrial emissions.

0.01

Mercury

Mercury may contaminate water supplies via

industrial emissions.

0.001

Nickel

Nickel is used in many industrial processes,

and may also be released from burning

fossil fuels.

0.02

Appendix4:Chemicalsofpotentialconcern


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Aesthetic/physiochemicalparameters

A number of chemical parameters may cause aesthetic or other

physiochemical issues if they are present at sufficient levels.

Table A4.2 provides a generic suite of these parameters.

TableA4.2:Aesthetic/physiochemicalparameters

Chemical

Australian

drinking water

guideline (mg/L)

Manganese

This level of manganese may cause staining of

laundry and plumbing fittings.

0.1

pH

Drinking water with increased acidity (pH less

than 6.5) can corrode plumbing fittings and

pipes. Drinking water with increased alkalinity

(pH greater than 8.5) can lead to encrustation

of plumbing fittings and pipes, and a pH above

11 may cause corrosion.

6.5-8.5

Sulfate

Sulfate may contribute to the corrosion of

plumbing fittings at this level.

250

Total dissolved solids (TDS)

Dissolved material (usually salts) can result

in scale developing on the inside of plumbing

fittings or lead to excess corrosion.

500

Total hardnessHardness is a measure of calcium and

magnesium in the water. Hard water may

contribute to the formation of scale on the

inside of plumbing fittings, and makes lathering

of soap difficult.

200


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Appendix5:Incidentrainwatertreatmentmicrobialcontamination

If it is suspected that water storages have been contaminated

corrective action should be taken. Corrective action would

normally involve controlling the source of contamination and

treating or disposing of contaminated water.

Water storages can be manually treated with chlorine if the

contamination is microbial. When treating contaminated

rainwater storages it is important not to over-dose the system,

and to follow occupational health and safety guidelines and

all safety and handling instructions provided on any chemical

containers.

To effectively treat rainwater storages a dose of 5 milligrams

per litre (mg/L) of chlorine is needed. This can be achieved

by adding:

125 millilitres (mL) of liquid bleach (4% available chlorine) to

every 1000 litres (kilolitre) of water in storage, OR

40 millilitres (mL) of liquid sodium hypochlorite (12.5%

available chlorine) for every kilolitre of water in storage, OR

8 grams (g) of granular calcium hypochlorite (65% available

chlorine) for every kilolitre of water in storage.

The concentrated chlorine mixture should be spread as widely

as possible across the storage surface to promote mixing.

The volume of water (in kilolitres) in a cylindrical tank can be

estimated using: V = D x D x H x 0.785, where D is the diameter

of the tank in metres and H is the depth of water in the tank

in metres.

Liquid bleach, sodium hypochlorite and calcium hypochlorite

can be purchased from large supermarkets, hardware stores or

swimming pool suppliers.

To ensure effective treatment, check that the free chlorine level

is 0.5 mg/L at the rainwater storage outlet 30 minutes after

treatment. A swimming pool test kit or dip strips (available from

pool shops and suppliers) can be used for this.Once the freechlorine level of 0.5 mg/L has been met flush the rainwater

distribution pipes with the treated water.

Note that disinfection with chlorine is only effective in controlling

microbial contaminants and will not reduce or remove

chemical contamination.



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australia; rainwater use in urban communities - victorian government

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